The engine mounted in an engine room of the vehicle is equipped with the intake system for introducing the intake air to cylinders. In the intake system of the engine, an element of an air cleaner removes the dust in the intake air, a resonance chamber reduces the intake noise, and an intake manifold introduces the intake to the respective cylinders.
There are some conventional intake systems of the engine which include an air cleaner that has an element disposed between upper and lower casings and that is integrated to an engine cover covering the top of the engine. Such conventional intake systems are disclosed in JP Laid-Open No. H11-125158 and JP Laid-Open No. 2003-161217.
However, in the conventional intake system of the engine, a filtering surface of the element located between the upper and lower casings is positioned generally horizontally. On this account, the intake air that flows generally horizontally along a lower surface of the engine cover should turn in a vertical direction (up and down) to pass the element. This results in an undesirable increase in the resistance of the intake air.
Also, the conventional intake system of the engine includes an intake duct for introducing the outside air to the air cleaner that extends longitudinally of the vehicle along the lower surface of the engine cover. On this account, when a resonance chamber casing that is connected to the air cleaner through a communication pipe is formed on the lower surface of the engine cover, an inner space of the engine cover is divided into two right and left spaces by the intake duct. The capacity of the resonance chamber is therefore not large enough, which detriments the effect of silencing noise and the intake noise cannot be reduced significantly.
Further, in the conventional intake system of the engine as disclosed in JP No. H11-125158, an inlet section of an upstream end of the intake duct opens to a front surface of the engine cover. On this account, the hot wind having passed a radiator forward of the engine is introduced upwardly along the engine and is inhaled by the intake duct, which increases the temperature of the intake air taken into the intake duct.
The purpose of the present invention is to provide an intake system of the engine which is disposed in a limited space above the engine, improves the engine performance by preventing increase in both the temperature and the resistance of the intake air, and also reduces intake noise.